The present invention generally relates to a semiconductor device and a method for manufacturing the same, and more specifically, to a technology of forming a device isolation film by a double Shallow Trench Isolation (STI) process, forming a first active region having a negative slope and a second active region having a positive slope and applying a recess region and a bulb-type recess region to the above-extended active region so as to prevent generation of horns in the active regions and to improve a channel length and area effectively.
As a result of high integration of semiconductor devices, a process margin for forming an active region and a device isolation film has been reduced. As a line width of a gate has become narrower, the channel length has also been reduced to degrade electric characteristics of semiconductor devices and generate a short channel effect. In order to prevent the degradation of semiconductor devices and the generation of the short channel effect, a recess gate obtained by etching a given depth of a semiconductor substrate of a local gate region has been used to increase the contact area between the active region and the gate and also increase the gate channel length.